Dear Hassan,
> > CSMA: Model theory for the operational semantics may be possible.
>
> Model Theory and Operational Semantics are orthogonal
> concepts. Model Theory fits unchanging truth. In this way,
> stateful computation such as that performed
> by PR systems is at odds with Model Theory.
for PR systems we need an intertwining of model theory
and a transition system formalism, since the state of
a PR system can be described as a "set of facts" (this
is the view/terminology of business rules approach),
or more formally as a set of (finite?) models, which
is transformed whenever a rule is fired.
> For an example of such a formal
> operational semantics, see a presentation I did this past
> summer for IFIP
> group on Rewriting (http://rewriting.loria.fr/IFIP-WG1.6/.
> Slides of my
> talk: http://koala.ilog.fr/wiki/bin/view/Main/HassanAitKaci#17.)
Interesting slides. However, notice that you've simplifed
a few things:
- Business rules are not production rules; business rules are
expressed by "business people" in plain English (and we have
to struggle formalizing them in some declarative logic, e.g.
in the restricted modal logic of SBVR); only after formalizing
a business rule you may try to implement it in the form of a
PR (but don't be surprised if this is not always the best
solution). In our case study
http://oxygen.informatik.tu-cottbus.de/rewerse-i1/?q=node/33#head-3
we show how plain English business rules can be (visually and XML)
formalized and then mapped to a concrete PR language (Jena and
JBoss/Drools).
- I cannot see how your definition of "Agenda" and the "pick"
operation captures what is really going on in PR engines
such as ILOG Jrules and JBoss/Drools.
In fact, the challenge seems to be to define a PR engine feature
set that allows to define/explain the different execution semantics
of the major PR engines.
-Gerd
-------------------
Gerd Wagner
http://oxygen.informatik.tu-cottbus.de/IT
Email: G.Wagner@tu-cottbus.de